<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <script>
    var arr = new Array(100,true,"hello");
    // var arr = [100,200,300];
    // for(var i=0;i<arr.length;i++){
    //   console.log(arr[i]);
    // }
    // for(var i in arr){
    //   console.log(arr[i]);
    // }
    // for(var a of arr){
    //   console.log(a);
    // }
    // arr.forEach(element => {
    //   console.log(element);
    // });
    console.log(arr);
    console.log(arr.push(123));
    console.log(arr);
    arr.unshift("false");
    console.log(arr);
    // console.log();
    // console.log(arr.pop());
    // console.log(arr);
    // console.log(arr.shift());
    // console.log(arr);
    var ele  = arr.concat([1,2,3,4,5]);
    console.log(ele);
    console.log(ele.splice(2,4));
    console.log(ele);
    console.log(ele.slice(2,4));
    console.log(ele);
    ele.reverse();
    console.log(ele);
  </script>
</head>
<body>
  
</body>
</html>